I feel your pain. I saw a production of 'Othello' at the Globe in London a few years ago. There was a man seated immediately behind us who was translating for his girlfriend (at a normal, conversational volume) the whole.way.through. Eventually both we, and 2 others people nearby asked him to stop. He got really indignant and said his grldfriend couldn't understand and we were being selfish. He only stopped after we spoke to a steward.
What got me, apart from the entitled attitude, was is that this production was sold out, and it sold out (except for standing room) really fast, so they almost certainly booked the tickets 2-3 months before the performance. And it is not exactly hard to get copies of the play in whatever language you want, in fact the theatre itself has a bookshop attached to it.
Dfortunately the steards, after speaking to him, stayed quite near by for the rest of the performance and when he started again about 10 minutes into the second act they reminded him and warned him he would have to leave if he didn't stop